Since I was about to finish my degree and make "lots and lots of money" as a computer engineer (actual starting salary: $52,500), we spent our future selves' money on plane tickets, eating out, and activities with the kids. In all, we racked up $20,000 in credit card debt—in addition to our student loans and financing two cars (one of them at 18% interest).

At the time, I was convinced that this debt would be "no problem"—that we'd pay it off in six months to a year after I started my shiny high-paying job. (Obviously my math blinders were on—the debt we acquired was more than my entire annual salary!)

I did graduate, and I did get the job—just in time, as our credit cards were all maxed out and my credit score had plummeted. Two years later, we have paid off less than half the debt we acquired in that year.

Moral of the story? Your future self is not nearly as rich as she/he looks. At least, not if you spend like I did!